Electric-current rectifier



July 31, 1928. I 1,678,825 5. RUBEN ELECTRIC CURRENT RECTIFIER Filed March 50, 1927 X METALLIC SULPHIDE AHOY {Gus I Cr O INVENTOR.

v BY

A TTORNEYS.

Patented July 31; 1928.

UNITED STATES PATENT OFFICE.

SAMUEL RUBEN, OF NEW YORK, N. Y., ASSIGNOR TO RUBEN RECTIFIER CORPORA- TION, OF ENGLEWOOD, NEW JERSEY, A CORPORATION ,OF DELAWARE.

ELECTRIC-CURRENT RECTIFIER.

Application filed March 30, 1927. Serial No. 179,479.

This invention relates to electric current rect-ifiers and the like' which employ asymmetric couples of the dry surface-contact variety.

Rectifiers of this variety are known which are characterized by the use of a body of relatively electropositive material, employed as one electrode element, disposed in electrical contact with a body of'relatively electronegative material employed as the other electrode element; there being an intervening film having inverse current-blocking properties. Such rectifiers depend for their operation upon the resistance and currentblocking characteristics of the film which forms as the result of electrochemical action.

Rectifiers depending on these characteristics known to the prior art, have been low in efliciency and limited in their application to small currents, because of improper conditions for film formation and maintenance, and become substantially inoperative after short periods of use.

The invention has for its object generally to provide an improved device of the character described, which is eflicient, economical and readily manufactured, and which provides an electroneg-ative electrode element having improved mechanical and electrical characteristics.

More specifically, an object is to provide an asymmetric couple which has an electronegative electrode element constructed so as to have both a relatively great mechanical resistance to compression and a high crystal density. I

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts, which will be exemplified in the constructions hereinafter set forth and the scope of the application of which will be indicated in the claims. A

For a fuller understanding of the nature and objects. of the invention, reference should be had to the following detailed description taken in connection with-the ac-v companying drawing,.in which: I Figure 1 shows diagrammatically a rectifying 'device constructed in accordance with the present invention; while Fig. 2 is a view showing in cross-section the electrode elements, indicating symbolically their composition when constructed in accordance with the present invention.

Referring now to the drawing, and particularly to Fig. 2, 10 denotes, the electropositive electrode element which is disposed cooperatively against an electronegative electrode element 11. These elements thus arranged comprise an asymmetric couple and are preferably placed between conducting terminal. electrode or end-plates, as shown at 12 in Fig 1, through which the circuit connections are preferably made.

The rectifying device or unit illustrated in Fig. 1 comprises two groups of two couples each, the groups being inverted with respect to each other and disposed adjacent the cen-- tral electrode" plate 13.

The end-plates at the ends of the assembled groups are adapted to be connected in conducting relation by means of a clamp-ing bolt 14; which passes through the couples,

but is insulated therefrom, as disclosed in,

my co-pending application Serial No. 7 50,-

939, filed November 18, 1924.. By this arrangement it is seen that the four couples comprise the arms of a Wheatstone bridge,

of which the terminals provided at 13 andv 14 comprise one diagonal thereof and serve as suitable terminals for the output circuit comprising conductors 15 and 16, leading respectively to the terminals of a direct-current-consuming device, here symbolically indicated by the signs and The nal plates 12, disposed intermediately of the inverted groups, provide the other diagonal of the Wheatstone bridge and serve as'suitable terminals for the alternating current input circuit here shown as comprising. the conductors 1 and 18, leading from the low tensionside of a suitable step-down transformer 19v here shown as connected to an termi- I not plate 12 connected to the conductor 17; and vice versa when the conductor 17 has .a' plus polarity.

The electropositive electrode element 10 is here a metallic body of substantially any relatively stable but highly active electropositive metal, for example, aluminum, boron, calcium, magnesium or zinc, such as taught in my co-pending application Serial .NO. 69,215, filed November 16, 1925.

The electronegative electrodeelement is a metallic compound of a highly electronegative element, which is adapted to form electrochemically an inverse current-blocking film when in contact with the electropositive electrode element. Metallic compounds with elements of the sixth group in the periodic table have this property, particularly maximum valent metallic sulphides, for example, plumbic sulphide, or cupric sulphide. Such sulphides comprise, of course. the basic material which renders operative the electronegative electrode element.

In the practice of the present invention the basic material of the electronegative electrode element is chemically compounded or alloyed with another material, which is electrode element. Consequently the adding of such high'resistance material results in an increase in the average resistance of the elec-' tronegative electrode element, which is desirable, since it insures a propermargin of safety in the resistance factor of the elec' trode, element which is depended upon to provide the energy of film-formation and -maintenance out of the IR-losses incident to the passage of current in the electrode element, as set forth in my co-pending applications Serial No. 38,780 filed June 22, 1925, and, Serial No. 113,009 filed June 1, 1926, so that there is an adequate supply of the energy necessary for film-formation and maintenance over a, relatively wide range of current variationJ Chromium type metals, thus introduced as a component of the electronegative electrode element, may be introduced in varying amounts, depending in a measure upon the range of current variation that the device is intended to operate over. There is, how-' ever, an upper limit to the amount which it isnot practical to exceed in commercial devices; this limit or maximum being substantially twenty percent (20%) by weight of added chromium type metal in the total mass of the electrode element. This is particularly true for the metal chromium, which, when introduced in the form of chromium trioxide, may be taken. in original amounts in a ratio substantially up to three parts of chromium trioxide to seven parts of basic material, as the chromium trioxide suffers reduction when thus combined.

Any suitable method may be adopted for the production of the electronegative elece trode element in accordance with the present invention; a preferred method for making first a mixing together in proper proportions as above indicated powdered cupric sulphide and powdered chromium trioxide. These ingredients, when properly mixed, are then fused together by the application of heat at a temperature in; the neighborhood of 500 C. and. cast into suitable forms which may thereafter be machined into the disc-like elements illustrated inthe drawing.

The addition of chromium to the electronegative electrode element imparts relatively great mechanical rigidity and strength to the cupric electrode elements, and have in consequence relatively great resistance to mechanical compression. The electronegative electrode elements, when thus constructed, have relatively high. internal resistance and high crystal density, and are able to resist compressional stresses up to a maximum in the neighborhood of 150 tons per square inch.

Since certain changes may be made in the above construction and dlfi'erent embodiments of the invention could be made without departing from-the scope thereof, it is intended that all matter contained in the 80 cupric-chromium elements, however, involves above description orshown in the accompanying drawing shall, be interpreted as illustrative, and not in a limiting sense. K

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In electric current like, of the dry surface-contact variety, an asymmetric couple having relatively electropositive. and electronegative electrode elements adapted for the electrochemical formation and maintenance at their contacting surfaces of an inverse current-blocking film, said electronegative electrode element comprising a metallic compound of an element of the sixth periodic group alloyed with an element of the chromium type.

2. In electric current rectifiers and the rectifiers and the i like, of the dry surface-contact variety, an

asymmetric couple having relatively electropositive and electronegative electrode elements adapted for the electrochemical formation and maintenance at their contacting.

surfaces of an inverse current-blocking film, said electronegative electrode element comprising a metallic sulphide and a compound of chromium, alloyed therewith.

3. In electric current rectifiers and the like, of the dry surface-contact vaniety, an

4:. In electric current rectifiers and the like, of the dry surface-contact variety, an asymmetric couple having relatively electropositive and electronegative electrode elements adapted for the electrochemical formation and maintenance at their contacting surfaces of an inverse current-blocking film, said electronegative electrode element comprising cupric sulphide and a quantity of an element of the chromium type united chemically so as to impart high density and mechanical rigidity to said element.

5. In electric current rectifiers and the like, of the dry surface-contact variety, an asymmetric couple having relatively electropositive and electronegative electrode elements adapted for the electrochemical formation and maintenance at their contacting surfaces of an inverse current-blocking film,

said electronegative electrode element comprising an alloy of cupric sulphide with chromium taken in an amount up to a limit of substantially 20% by .weight of the total mass of said element.

6.'In electric current rectifiers and the like, of the dry surface-contact variety, an

asymmetric couple having relatively electropositive and clectronegative electrode elements adapted for the electrochemical for mation and maintenance at their contacting surfaces of an inverse current-blocking film, said electronegative electrodeelement comprising. a fused mass of cupric sulphide and chromium trioxide, the latter bein taken in an amount suflicient to provide t e energy for the formation and maintenance of the inverse current-blockin film from the resistance losses incident to t 1e passa 'e of current.

7 In electric current rectifiers and the like, of the dry surface-contact variety, an asymmetric couple having relatively electropositive and electronegative electrode elements adapted for the electrochemical formation and maintenance at their contacting surfaces of an inverse current-blocking film, said electronegative electrode element comprising a fused mass of cupric sulphide and chromium trioxide taken in an amount not to exceed a maximum limit of 20% by weight of chromium in the mass of the electronegative electrode element.

I In testimony whereof I aflix my signature.

SAMUEL RUBEN. 

